Work sheet conveying device

ABSTRACT

The present invention provides a work sheet conveying device having a traveling member with a compact work sheet holder, making it possible to improve work sheet conveying speed and to reduce the time required for acceleration and deceleration, the work sheet conveying device further making it possible to improve the efficiency with which small work sheet&#39;s are conveyed. The work sheet conveying device includes a plurality of traveling members  13, 14  that can travel independently along a plurality of tracks  11, 12  installed parallel to one another between a work sheet processing machine  1  and a work sheet placement portion. Each of the traveling members has a work sheet holder  19, 20  that holds a work sheet. A part of the work sheet holder  19, 20  is configured as an expanding portion  26  the position of which can be changed to a traveling area R 1,  R 2  for the traveling member traveling along the adjacent track. The device selectively performs an individual conveying operation of allowing each of the traveling member to hold and individually convey the work sheet using the work sheet holder  19, 20  and a cooperative conveying operation of allowing the plurality of traveling members  13, 14  to hold and convey the same work sheet using the respective work sheet holders  19, 20  with the position of the expanding portion  26  changed.

FIELD OF THE INVENTION

The present invention relates to a work sheet conveying device which carries a material work sheet into a work sheet processing machine and which carries out a product work sheet processed by work sheet processing.

BACKGROUND OF THE INVENTION

In some work sheet conveying devices of this kind, a traveling member traveling along a predetermined track has a plurality of suction pads. These work sheet conveying devices thus convey a work sheet by using the suction pads to suck and hold the work sheet. In general, the suction pads are arranged so as to be able to handle the largest work sheet. As a special type, a work sheet conveying device is known which changes the intervals between the suction pads in association with the size or shape of the work sheet (for example, the Unexamined Japanese Patent Application Publication (Tokkai) No. 2000-117373.

To stably convey a work sheet, it is preferable to use the suction pads to suck the vicinity of each edge of the work sheet. Thus, a large number of suction pads need to be arranged over a wide range, resulting in the need to increase the scale of a work sheet holder composed of the suction pads and a support frame therefor. This is not limited to common work sheet conveying devices and also applies to the invention described in Unexamined Japanese Patent Application Publication (Tokkai) No. 2000-117373. With the large-scale work sheet holder, the weight of the device itself makes it difficult to increase the speed of the traveling member and to reduce the time required for acceleration and deceleration.

An attempt was made to provide a plurality of traveling members each having a work sheet holder and cooperating with one another in conveying a work sheet. This configuration enables a reduction in the size of the work sheet holder of each traveling member, allowing an increase in the speed of the traveling member and a reduction in the time required for acceleration and deceleration. Furthermore, relatively small work sheets are individually conveyed by the traveling members, enabling conveying efficiency to be drastically improved.

To achieve this attempt, it is necessary that the traveling members travel along parallel different tracks so that the two adjacent traveling members can pass each other without having the work sheet holders thereof interfere with each other and that the traveling members can stably hold the same large work sheet using the work sheet holders thereof. A technique enabling these operations needs to be established.

SUMMARY OF THE INVENTION

An object of the present invention is to solve the above-described problems to provide a work sheet conveying device having a traveling member with a compact work sheet holder, making it possible to improve work sheet conveying speed and to reduce the time required for acceleration and deceleration, the work sheet conveying device further making it possible to improve the efficiency with which small work sheets are conveyed. Another object of the present invention is to make it possible to easily switch between a state in which work sheet holders of a plurality of traveling members hold the same work sheet and a state in which the work sheet holder of each of the traveling members individually holds a work sheet. Yet another object of the present invention is to, where the work sheet holders of the plurality of traveling members hold the same work sheet, allow the work sheet holders to hold as large a work sheet as possible.

A work sheet conveying device according to the present invention comprises a plurality of tracks installed parallel to one another between a work sheet processing machine and a work sheet placement portion, and a plurality of traveling members that can travel independently along the respective tracks. Each of the traveling members has a work sheet holder that holds a work sheet, and a part of the work sheet holder is configured as an expanding portion a position of which can be changed to a traveling area for the traveling member traveling along the track adjacent to the track along which the above-described traveling member having the work sheet holder travels. The device selectively performs an individual conveying operation of allowing each of the traveling members to hold and individually convey the work sheet using the work sheet holder, and a cooperative conveying operation of allowing the plurality of traveling members traveling along the adjacent tracks to hold and convey the same work sheet using the respective work sheet holders with the position of the expanding portion changed. The term “traveling area” as used herein refers to an area through which the work sheet holder with the position of the expanding portion unchanged passes as a result of traveling of the traveling member.

With this configuration, the position of the expanding portion of the work sheet holder is changed to the traveling area for the traveling member traveling along the adjacent tracks so that the work sheet holders of the plurality of traveling members can hold the same large work sheet with the vicinity of each edge of the work sheet fixed. Thus, the plurality of traveling members can cooperate with one another in stably conveying the large work sheet. Furthermore, with the position of the expanding portion of the work sheet holder not changed to the traveling area for the traveling member traveling along the adjacent track, the two traveling members traveling along the adjacent tracks can pass each other without having the work sheet holders interfere with each other. Thus, the individual traveling members can independently convey relatively small work sheets. Since the plurality of traveling members cooperate with one another in conveying the large work sheet, the size of the work sheet holder of each traveling member can be reduced, enabling an increase in the speed of the traveling member and a reduction in the time required for acceleration and deceleration. Furthermore, since each of the traveling members individually travels the relatively small work sheets, it is possible to improve the efficiency with which the relatively small work sheets are conveyed.

The expanding portion of the work sheet holder preferably changes the position thereof by turning around a central shaft extending in a vertical direction. Where the expanding portion is configured to turn around the central shaft extending in the vertical direction, it is possible to easily switch between the state in which the work sheet holders of the plurality of traveling members hold the work sheet and the state in which the work sheet holder of each of the traveling members individually holds the work sheet.

The expanding portions of the work sheet holders in the two traveling members traveling along the adjacent tracks are desirably provided on opposite sides in a traveling direction. Where the expanding portions of the work sheet holders in the two traveling members traveling along the adjacent tracks are provided on the opposite sides in the traveling direction, where the work sheet holders of the plurality of traveling members hold the same work sheet, the work sheet holders can hold as large a work sheet as possible.

The work sheet conveying device according to the present invention comprises the plurality of tracks installed parallel to one another between the work sheet processing machine and the work sheet placement portion, and the plurality of traveling members that can travel independently along the respective tracks. Each of the traveling members has the work sheet holder that holds the work sheet, and a part of the work sheet holder comprises the expanding portion the position of which can be changed to the traveling area for the traveling member traveling along the track adjacent to the track along which the above-described traveling member having the work sheet holder travels. The device selectively performs the individual conveying operation of allowing each of the traveling members to hold and individually convey the work sheet using the work sheet holder, and the cooperative conveying operation of allowing the plurality of traveling members traveling along the adjacent tracks to hold and convey the same work sheet using the respective work sheet holders with the position of the expanding portion changed. Thus, the traveling members travel along the parallel different tracks, and the two adjacent traveling members can pass each other without having the work sheet holders interfere with each other. Furthermore, the work sheet holders of the traveling members can stably hold the same large work sheet. This makes it possible to make the work sheet holder of each traveling member compact, allowing the improvement of a work sheet conveying speed and a reduction in the time required for acceleration and deceleration. Additionally, the efficiency with which small work sheets are conveyed can be improved.

Where the expanding portion of the work sheet holder is configured to change the position thereof by turning around the central shaft extending in the vertical direction, it is possible to easily switch between the state in which the work sheet holders of the plurality of traveling members hold the same work sheet and the state in which the work sheet holder of each of the traveling members individually holds the work sheet.

Where the expanding portions of the work sheet holders in the two traveling members traveling along the adjacent tracks are provided on the opposite sides in the traveling direction, where the work sheet holders of the plurality of traveling members hold the same work sheet, the work sheet holders can hold as large a work sheet as possible.

Other features, elements, processes, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a work sheet processing system comprising a work sheet conveying device according to an embodiment of the present invention.

FIG. 2 is a side view of traveling members and work sheet holders in the work sheet conveying device.

FIG. 3 is a plan view of the work sheet holder.

FIGS. 4A to 4C are plan views of the work sheet holders, showing that the work sheet holders hold different work sheets.

FIG. 5 is a plan view of a different work sheet holder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a perspective view of an entire work sheet processing system comprising a work sheet processing machine 1, a work sheet conveying device 2, a palette 9 and a work sheet transporting vehicle 3 which serve as a work sheet placement portion, and a work sheet stocker 4. The work sheet processing system further comprises a work sheet carry-in device (not shown in the drawings) that carries a material work sheet WO into the work sheet processing machine 1. However, the description of the work sheet carry-in device is omitted.

The work sheet processing machine 1 comprises a function of cutting a plurality of product work sheets W from the material work sheet WO on a table 5 by means of punching or the like. The work sheet processing machine 1 is composed of a punch press, a laser processing machine, or the like. In this example, the work sheet processing machine 1 is a punch press comprising a processing portion 7 that elevates and lowers a punch tool (not shown in the drawings) with respect to a die tool (not shown in the drawings), and a work sheet feeding mechanism 8 that moves the material work sheet WO forward and backward (Y direction) and rightward and leftward (X direction) on the table 5.

The work sheet stocker 4 is a device that lays the product work sheets W on top of one another in a stack on a palette 9; the product work sheets W are to be processed by the work sheet processing machine 1. The work sheet stocker 4 has a multi-stage shelf 4 a on which the palette 9 is placed. In the work sheet stocker 4, the palette 9 on any stage of the shelf 4 a is movable forward and backward between a work sheet placement position located backward in FIG. 1 and a storage position to which the palette 9 moves forward from the work sheet placement position.

In the present embodiment, the work sheet conveying device 2 is a device that carries out the product work sheet W processed by the work sheet processing machine 1 to the palette 9 or the work sheet transporting vehicle 3. The work sheet transporting device 2 comprises two tracks 11, 12 installed parallel to each other between a position where the work sheet processing machine 1 is stopped and a position where the work sheet transporting vehicle 3 is stopped, the tracks 11, 12 facing in a lateral direction, and the traveling members 13, 14 being independently travelable along the tracks 11, 12.

The two tracks 11, 12 are integrally coupled together at laterally opposite ends thereof. The tracks 11, 12 are supported by a lateral pair of forward-backward moving frames 16. Each of the forward-backward moving frames 16 is movable along a forward-backward moving rail 18. The forward-backward moving frame 16 can be moved forward and backward by a forward-backward movement driving source (not shown in the drawings). The forward-backward movement driving source is composed of, for example, a servo motor and a converting mechanism such as a ball screw which converts rotation of the servo motor into a linear motion.

FIG. 2 is a side view of the traveling members 13, 14. The traveling members 13, 14 are provided on the tracks 11, 12 so as to be travelable along the tracks 11, 12 via guide members (not shown in the drawings). The traveling members 13, 14 are self-propelled by traveling driving sources (not shown in the drawings) such as servo motors. The guide members are, for example, linear roll bearings or guide rollers, and are each interposed between a bases 23 of the traveling member 13, 14 and the track 11, 12.

The traveling members 13, 14 have work sheet holders 19, 20, respectively, which hold work sheets. As shown in FIGS. 2 and 3, each of the work sheet holders 19, 20 is composed of a laterally long pad support plate 21 and a plurality of suction pads 22 attached to the pad support plate 21. As shown in the partly enlarged view in FIG. 2, each of the suction pads 22 is composed of a bundle of a plurality of unit suction pads 22 a individually connected to a vacuum source via throttled path. The suction pads 22 can suck a suction target such as the product work sheet W even if any of the suction pads are located off the suction target. Each suction pad 22 as a whole may constitute one negative pressure portion instead of being composed of the bundle of unit suction pads.

The work sheet holders 19, 20 can be elevated and lowered with respect to the bases 23 of the traveling members 13, 14, respectively. In the present embodiment, a vertically long elevating and lowering member 24 is fitted into each of the bases 23. The pad support plate 21 is attached to a lower end of the elevating and lowering member 24. The elevating and lower member 24 is elevated and lowered by an elevating and lowering driving source (not shown in the drawings). The elevating and lowering driving source may be provided separately from the traveling member 13, 14 or the base 23 itself may serve as the elevating and lowering driving source.

On the work sheet holders 19, 20 of the traveling members 13, 14, the suction pads 22 are arranged in almost the same manner in a normal state shown by a solid line in FIG. 3. That is, on each of the work sheet holders 19, 20, the suction pads 22 are provided in two rows, a front row and a second row, each of which includes a plurality of the suction pads 22. The lateral position of each of the suction pads 22 in one of the rows almost aligns with that of the corresponding suction pad 22 in the other row. The suction pads 22 are arranged such that the front row extends further leftward than the rear row. The extended portion constitutes a small article holding portion 25.

Further, each of the work sheet holders 19, 20 has an expanding portion 26 the position of which can be changed to a traveling area R1, R2 for the traveling member traveling along the adjacent track as shown by a chain line in FIG. 3. The term “traveling area” as used herein refers to an area through which the work sheet holder 19, 20 with the position of the expanding portion unchanged passes as a result of traveling of the traveling member 13, 14. For the work sheet holder 19 of the front traveling member 13, the left side of the rear row constitutes the expanding portion 26. For the work sheet holder 20 of the rear traveling member 14, the right side of the front row constitutes the expanding portion 26. That is, the expanding portions 26 of the work sheet holders 19, 20 are provided opposite each other and on the opposite sides in the traveling direction. In the expanding portion 26, a portion 21 a of the pad support plate 21 is supported so as to be turnable around a central shaft extending in a vertical direction. The pad support plate turning portion 21 a is turned by a turning driving source 28 such as a fluid cylinder.

In the work sheet conveying device 2, the forward-backward moving frame 16 moves forward and backward along the forward-backward moving rail 18, and the traveling members 13, 14 travel along the tracks 11, 12. Furthermore, the work sheet holders 19, 20 elevate and lower to convey the product work sheet W held on the work sheet processing machine 1 to the palette 9 or the work sheet transporting vehicle 3, which serves as a work sheet placement portion. The work sheet holders 19, 20 the product work sheet W as shown in FIGS. 4A to 4C.

That is, a small product work sheet W1 is sucked and held by the suction pads 22 on the small article holding portion 25 of the work sheet holding portion 19 (20) as shown in FIG. 4A. This is because the use of the suction pads 22 on the small article holding portion 25, located at the left end of the front row, easily prevents the work sheet holder 20 from interfering with the work sheet processing machine 1. A medium-sized product work sheet W2 is sucked and held by some or all of the suction pads 22 on the work sheet holder 19(20) as shown in FIG. 4B.

Furthermore, for a large product work sheet W3, as shown in FIG. 4 c, the two traveling members 13, 14 are stopped side by side on the tracks 11, 12. Then, the position of the expanding potion 26 of each of the work sheet holders 19, 20 are changed to the corresponding traveling area R1, R2 for the traveling member traveling along the adjacent track. The work sheet holders 19, 20 thus suck and hold the product work sheet W3. Where the work sheet holders 19, 20 of the two traveling members 13, 14 thus hold the same work sheet W3, even the large work sheet W3 can be sucked by the suction pads 22 at the vicinity of each edge of the work sheet W3. This enables the work sheet W3 to be stably conveyed. The size of the product work sheet W3 can be dealt with by displacing the relative positions of the traveling members 13, 14 in the traveling direction.

Thus, various work sheets of different sizes can be efficiently conveyed by selectively performing the individual conveying operation of allowing each of the traveling member 13, 14 to hold and individually convey the relatively small work sheet W1, W2 using the work sheet holder 19, 20 and the cooperative conveying operation of allowing the two traveling members 13, 14 to hold and convey the same large work sheet W3 using the work sheet holders 19, 20. During the cooperative conveying operation, the position of the expanding portion 26 of each of the work sheet holders 19, 20 is changed to the travel area R1, R2 for the traveling member traveling along the adjacent track to increase the range within which the suction pads 22 are arranged. Thus, the vicinity of each edge of the work sheet W3 can be fixed by the suction pads 22, allowing the large work sheet W3 to be stably conveyed. Furthermore, with the expanding portion 26 of the work sheet holder 19, 20 not changed to the traveling area R1, R2 for the traveling member traveling along the adjacent track, the two traveling members 13, 14 can pass each other without having the work sheet holders 19, 20 thereof interfere with each other. Thus, the individual traveling members 13, 14 can independently convey the relatively small work sheets W1, W2, improving the efficiency with which the relatively small work sheets W1, W2 are conveyed. In both work sheet holders 19, 20, the suction pads 22 are arranged in almost the same manner, allowing the same type of work sheets to be similarly held. Moreover, the two traveling members 13, 14 are configured to cooperate with each other in conveying the large work sheet W3, enabling a reduction in the size of the work sheet holder 19, 20 of each traveling member 13, 14. This in turn allows an increase in the speed of the traveling member 13, 14 and a reduction in the time required for acceleration and deceleration. Furthermore, the distance between the tracks 11, 12 can be reduced, making it possible to make the entire work sheet conveying device 2 compact.

The work sheet conveying device is configured such that the expanding portion 26 of the work sheet holder 19, 20 changes the position thereof by turning around the central shaft 27 extending in the vertical direction. This makes it possible to easily switch between the state in which the work sheet holders 19, 20 of the two traveling members 13, 14 hold the work sheet and the state in which the work sheet holder 19, 20 of each of the traveling members 13, 14 individually holds the work sheet. The position of the expanding portion 26 may be changed by, for example, moving a portion 21 b of the pad support plate 21 in a direction orthogonal to the traveling direction of the traveling member as shown in FIG. 5 instead of using the configuration in which the expanding portion 26 is turned. Although a support mechanism and a moving mechanism for the pad support plate moving portion 21 b are not specifically shown in the figures, any appropriate mechanisms may be adopted.

Furthermore, the expanding portions 26 of the work sheet holders 19, 20 are provided on the opposite sides in the traveling direction. Consequently, with the position of the expanding portion 26 changed, the suction pads 22 are arranged over a wide range. A large work sheet can thus be held by both work sheet holders 19, 20.

The present embodiment is configured such that the two traveling members 13, convey the large work sheet W3. However, at least three traveling members may convey the work sheet W3. Furthermore, in the present embodiment, the work sheet conveying device 2 is used to carry out the product work sheet W from the work sheet processing machine 1. However, the work sheet conveying device 2 may be used to carry the material work sheet WO into the work sheet processing machine 1.

While the present invention has been described with respect to preferred embodiments thereof, it will be apparent to those skilled in the art that the disclosed invention may be modified in numerous ways and may assume many embodiments other than those specifically set out and described above. Accordingly, it is intented by the appended claims to cover all modifications of the present invention that fall within the true spirit and scope of the invention. 

1. A work sheet conveying device characterized by comprising: a plurality of tracks installed parallel to one another between a work sheet processing machine and a work sheet placement portion; and a plurality of traveling members that can travel independently along the respective tracks, and in that each of said traveling members has a work sheet holder that holds a work sheet, a part of the work sheet holder is configured as an expanding portion a position of which can be changed to a traveling area for the traveling member traveling along the track adjacent to the track along which the traveling member having the work sheet holder travels, and the work sheet conveying device selectively performs an individual conveying operation of allowing each of the traveling members to hold and individually convey the work sheet using the work sheet holder, and a cooperative conveying operation of allowing the plurality of traveling members traveling along the adjacent tracks to hold and convey the same work sheet using the respective work sheet holders with the position of the expanding portion changed.
 2. A work sheet conveying device according to claim 1, characterized in that the expanding portion of the work sheet holder changes the position thereof by turning around a central shaft extending in a vertical direction.
 3. A work sheet conveying device according to claim 2, characterized in that the expanding portions of the work sheet holders in the two traveling members traveling along the adjacent tracks are provided on opposite sides in a traveling direction. 